Most reduction machines in the prior art provide discrete reduction ratios, i.e., two or three reduction settings such as 75% and 66%, which enable reduction copying at only those particular ratios. This type of machine is sometimes wasteful since a document which is too big to be reduced to the copy paper size at 75% may nevertheless be copied at that setting before the operator is able to determine the necessity of moving to the greater reduction ratio. In a continuously variable reduction machine, some indication of the area of the document glass to be copied for any particular reduction setting is a necessity since the infinite variation in settings between the boundaries could result in numerous copies of either not enough reduction or too much reduction if no indicators are used. This problem was recognized in the prior art in U.S. Pat. No. 3,395,610, FIG. 16 thereof, which uses a reduction indicator, continuously variable in position, to signal one boundary of the document area to be copied. This indicator is operator viewable through the document glass. Similarly, U.S. Pat. No. 2,927,503; FIG. 15 thereof, shows rails which are continuously variable to frame the area of the document glass to be copied, the rails visible through the document glass.
In a continuously variable reduction machine there are two factors affecting the choice of reduction ratio: first is the document size and second is the copy paper size. In the prior art mentioned above, U.S. Pat. No. 2,927,503 operates so that in all formats the middle of the document is automatically copied onto the middle of the copy paper. The machine disclosed does not appear to be capable of utilizing two different sizes of copy paper, but were such the case, and if the indicators were coordinated with the smaller copy paper size, the larger copy paper size would always be unfilled at the edges. Similarly, in U.S. Pat. No. 3,395,610; the machine does not appear to be designed for use with two different copy paper sizes. Were it so designed, again the larger copy paper would always be unfilled. In fact, in this particular machine, even the smaller size copy paper is unfilled since overreduction is always practiced.
Therefore, it is the primary object of the instant invention to provide indicators for continuously variable reduction apparatus capable of utilizing two or more different sizes of copy paper.